Method and apparatus for separating and washing materials



METHOD AND APPARATUS 'FOR SEPARATING AND WASHING MATERIALS H. R. RAFT'ON April 16, 1935.

Filed July 17, 1 5 Sheets-Sheet 1 April- 16, 1935. I RAFTON 1,997,915

METHOD AND APPARATUS FOR SEPARATING AND WASHING MATERIALS Filed July 17, 1929 Sheets-Sheet 2 mantoz A ril 16, 1935. a H. R. RAFTON I 1,997,915

METHOD AND APPARATUS FOR SEPARATING AND WASHING MATERIALS Filed July-17, 1929 ,5 Sheets-Sheet 3 attmq "A ril 16, 1935. H. R. RAFTQN' METHOD AND APPARATUS FOR SEPARATING AND WASHING MATERIALS 5 Sheets-Sheet 4 I Filed July 17, 1929 QmwN- A ril 16, 1935. H. R, RAFTON 1,997,915

METHOD AND APPARATUS FOR SEPARATING AND WASHING MATERIALS Filed July 17, 1929 5 Sheets-Sheet 5 wi ow/grgqpmv Patented Apr. 16, 1935 PATENT OFFICE METHOD AND\APPARATUS FOR SEPARAT- ING AND WASHING MATERIALS Harold Robert Rafton,

to Rafton Engineering tion of Massachusetts Andover, Mass., assignor Corporation, a corpora- Application July 17, 1929, Serial No. 879,004

3 Claims.

This invention relates to method and apparatus for separating and washing materials, and more particularly slurries of the type occurring in the manufacture of paper pigments.

In the manufacture of paper pigments, the concentration of pigment in the slurry may be as high as twenty per cent. or more by weight, and the separation. of grit from the fine particles and solubles in the slurry is attended with difficulties, particularly in providing continuously operating means of substantial capacity. In my copending application Serial No. 359,943, filed May 2nd, 1929, I have shown, described and claimed a screening device suitable for use with a gyratory frame which is particularly adapted for this purpose, but it is necessary to provide a number of the screening devices in order to separate relatively large quantities of slurry, the capacity of each screening device being relatively limited. The present invention contemplates in part the provision of an apparatus which is adapted for use in connection with the screening device disclosed in my copending application referred to,

but is not necessarily limited to such a device.

An impcrtant object of the present invention is to provide a novel method of separating materials containing solids and liquids wherein a substantially complete separation is readily effected.

A further object is to provide a method of the character referred to which is substantially continuous in operation and which is particularly adapted for handling relatively large quantities of material.

A further object is to provide a method of separating grit from the finer particles and solubles in paper pigment slurries and wherein the separation is substantially complete and relatively rapidly carried out.

A further object is to provide a novel form of apparatus for separating solid material of sub-'- stantial size from liquids and finer particles, particularly with reference to the separation of grit from thefiner particles and solubles contained in the slurries occurring in the manufacture of paper pigments.

A further object is to provide a novel apparatus of the character referred to which is substantially continuous in operation and is adapted to effect the relatively rapid separation of large quantities of material.

A further object is to provide an apparatus of novel character wherein the material is subjected to an initial treatment to effect a substantially complete separation of the greater portion of the geously may finer particles and solubles in the slurry from the grit and wherein the grit thus separated is subjected to the action of a current of a washing quid to effect a substantially complete separation from the grit of the solubles and/or finer particles adhering thereto-after the initial separation.

A further object is to provide a novel form of apparatus of the character referred to having safety means for positively preventing any coarse material or grit from finding its way into the fine material and solubles as would be caused by the breaking of a screen, the overloading of an initial separator, etc.

A further object is to'provide novel mechanical means for initially separating the greater portion of the finer material and solubles from the grit in slurries, and for conveying the grit thus separated to a discharge point and at the same time subjecting the grit to the action of a washing liquid to separate therefrom the solubles and/or finer materials adhering thereto.

A further object is to provide a combined washing machine and classifier particularly adapted for use in the treatment of slurries occurring in the manufacture of paper pigments whereby the grit in such slurries may be separated therefrom substantially completely free from adhering fine material and solubles.

A further object is to provide an apparatus of the character referred to wherein a plurality of initial mechanical separating devices is em-. ployed to receive the slurry, and to provide novel feeding means for the separators to effect a substantially uniform and constant feed thereto without the usual settling of the slurry and the consequent choking of the feed pipes. Other objects and advantages of the invention will become apparent during the course of the following description.

I have discovered that in the manufacture of paper pigments advantasolubles adhering thereto, the grit thus separated the slurries occurring be subjected to a mechanical separating action to substantially completely sep- ,bles in the slurry, but that the eificiency of such that after the greatadvantageously may be subjected to the action of a relatively small quantity of a washing liquid such as water to substantially completely remove the adhering material from the grit so as to permit its recovery without undue dilution.

The method resulting from such discovery consists in subjecting the slurries to the action of mechanical separating means to effect a substantially complete separation of the greater portion of the fines and solubles from the grit and the subjection of the grit thus separated to the action of a preferably flowing stream of a washing liquid such as water to eflect a washing action whereby only relatively clean grit will be discarded. The grit is preferably moved during such washing action as by means of a discharging conveyor, and the movement of the grit is preferably carried out counter to the current of the washing liquid.

As previously stated, it has been found that.

such a washing action is substantially complete in its results, and may be effected with a relatively slow flow of water so as not to unduly dilute the fine material and solubles, and these materials, flowing counter to the movement of the grit, are readily recoverable for commercial use and may preferably be mixed with the slurry in the tank from which the headbox of the initial separating means is fed.

In the drawings I have shown one form of apparatus elements particularly adapted for practicing the method. In this showing,

Figure 1 is a plan view, parts being omitted,

Figure 2 is an end elevation, parts being omitted,

Figure 3 is a section on line 3-3 of Figure 1, parts being omitted,

Figure 4 is a transverse section on line H of Figure 3, parts being omitted,

Figure 5 is a section on line 5-3 of Figure 1,

Figure 6 is a detail section on line 3-6 of Figure 5.

Figure 7 is a similar view on line of Figure 5,

Figure 8 is a side elevation of a gyratory separating device adapted for use in connection with the apparatus, and,

Figure 9 is a transverse vertical sectional view.

taken through the pan and associated elements of the gyratory separating device.

Referring to Figures 1 to 4 inclusive, the nu- -meral l designates a plurality of vertical posts connected by transverse braces II and longitudinal braces l2 forming a main frame. An auxiliary frame is auanged adjacent the main frame and similarly includes vertical posts l3 connected by horizontal braces l4 and'longitudinal braces 5. The main frame of the apparatus is provided at one side of the longitudinal center thereof with a plurality of pans or containers each indi-' cated as a whole by the numeral I6, and at the opposite side of its longitudinal center with a second series of pans or containers l1 somewhat similar in character. Each of the pans i6 is provided with side walls or partitions l3, and from each of the partitions, the bottom of each pan slopes downwardly as at l8 toward an intermediate bottom 20 which slopes downwardly toward the longitudinal center of the apparatus for communication with a transverse conduit 2|. Each pan I 6 is further provided with outer and inner walls 22 and 23 the latter of which is notched as at 24 fora purpose to be described.

Each of the pans I1 is arranged opposite one of the pans l6 and is somewhat similar in construction thereto. As distinguished from the pans l6, however, each pan I1 is provided with downwardly sloping bottoms 25 to feed material toward a discharge opening 26 arranged in one corner of the pan and communicating with an outlet pipe 21 (see Figure 4). Each pipe 21 is connected to a horizontally extending pipe 28 which terminates in a downtumed end 29, for a purpose to'be described. The pans'l'l also are, provided in their inner walls with notches corresponding to the notches 24. 1

A longitudinally extending trough 30 is arranged centrally of the main frame and is supported in any suitable maimer between the central pairs of posts Ill. The trough 30 includes side walls 32 and a sloping bottom 33, such bottom being clearly shown in Figure 3 of the drawings and being inclined upwardly toward the outlet end of the apparatus where the trough 30 verse center of the trough 30 to the outlet end thereof, a plate 4| preferably extends across the trough beneath the'upper runs of. the chains 38, for a purposeto be described. Water or other washing liquid is supplied to the upper end of the trough 30 from a suitable source through a pipe 38' controlled by .the valve 31'.

The shaft 36 extends through slots 42 formed in the side walls of the trough, and the outer.

ends of the shaft are preferably supported in bearings 43 adjustable by screws 44 to take up slack in the chains 38. A sprocket 45 is connected to one end'of the shaft 36. A drive chain 46 passes around the sprocket 45 and around a driving sprocket 41 carried by a shaft 48 extending from a suitable speed reduction device 49. Power for the speed reduction device may be furnished by any suitable type of mot-01,50.

Adjacent the end of the apparatus opposite the discharge spout 34 a baille plate extends downwardly into the trough 30', and the trough communicates beneath the baiile plate. 5| with a transverse duct 52 extending along the end of the apparatus and communicating at its lower end with alongitudinal trough 53 arranged outwardly of the main frame posts ID. The bottom of the trough 53 inclines downwardly toward its end opposite the duct 52 and at that end is provided with an outlet opening 54 communicating with a take-oil pipe 53 for a purpose to be described.

The auxiliary frame of the apparatus supports a plurality of auxiliary pans or receptacles 58 which correspond in arrangement and are similar to the pans I1. One wall 57 of the trough 53 forms the inner wall of the pans 56 and is provided with notches similar to the notches 24 for a purpose to be described. Each pan 58 is provided with sloping bottom portions 58 to feed material in the pan toward a discharge opening 59 communicating with a take-off pipe 60 (see Figures 2 and 4). I

Each of the pipes 30 communicates through a valve M with a common take-01f pipe 62 from which material flowing from the pans 5t may be collected.

Each of the pans ii and 56 is adapted to receive a separating device or screen such as a gyratory riddle employing the screening device disclosed in my copending application Serial No. 359,943, referred to above. These screens are shown" in dotted lines, indicated by the numeral 63. The screens are preferably of the gyratory type disclosed in my copending application referred to, the fine material and solubles being discharged through a bottom screening element into the respective fans, while the coarse material is discharged from above the screen by an outlet spout 6 3. The outlet spouts 65 extend through the notches 12 3 in the walls of pans it, H and 56 respectively, and discharge into trough 36 in the case of pans i6 and Ill, and into trough 53 inthe case of pans 56. I prefer to employ screens of the type referred to because they have been found to be particularly eflicient in opera- 13 communicates with tion, but it will become apparent that any-suitable riddle or other separating device may be em-' ployed.

Referring to Figures 1, 2, 5, 6 and 7, the numeral t designates a headbox as a whole which has been found to be particularly satisfactory for uniformly supplying material to be separated and washed to the various separators $3. The headbox is preferably arranged transversely of the apparatus above the discharge end thereof, as shown in Figure 2. The headbox includes side walls 68, the lower portions of which are inclined downwardly toward each other to provide a relatively narrow flat bottom bl. -Material is fed into the headbox through an inlet pipe 68 communicating-therewith through one of the side walls adjacent the end of the headbox, and a bafile plate 69 extends across the top of the headbox and downwardly substantially centrally thereof, as shown in Figure 7, to prevent the incoming material from splashing out of the box.

The bottom wall of the headbox is provided adjacent the end thereof opposite the inlet pipe 68, with an outlet pipe Id, and the headbox also is preferably provided, in a side wall thereof, above the discharge pipe It, with an overflow pipe H which is adapted to prevent the headbox from overflowing in the event of the cloggingof the pipe ill or the feeding of the material into the headbox at too rapid a rate.

At a point spaced slightly inwardly from the discharge end of the headbox,'the latter is provided with a vertical wall H the height of which determines the height of the material in the headbox between the wall 12 and the inlet pipe 6%. The bottom 67 of the headbox is provided with a plurality of openings 13 corresponding in number to the pans i6 and ill, and each opening a take-off pipe id. The openings 13 are spaced between the wall 12 and the end of the headboxadjacent the inlet pipe 6%.

Each of the take-off pipes 16 is connected to a suitable manually controlled valve 85 which in turn, communicates with a vertical pipe I6. Each of the pipes I6 communicates with an inwardly extending horizontal pipe H which communicates in turn through a cross IS with another pipe It arranged at right angles thereto, the pipes I8 being inclined downwardly to prevent plugging;

and extending longitudinally of the separating apparatus above the central portion thereof. The various pipes ll and 18 are arranged at difterent heights, as shown in Figure 2, as a matoperation to take care of thus prevent the headbox ter of convenience and accessibility. Each of the pipes it is connected at its lower end to a T M, one branch of which is connected to a horizontally extending pipe 82 provided at its extremity with a depending discharge nozzle 83. The bodies of the crosses it, and the T's 85, are preferably provided with clean-out plugs 83 which may be removed to permit the tees and crosses to be cleaned when desired. The vertical angle irons Bit, and the horizontal angle irons 85 attached thereto serve as a support for the piping system connected to the headbox.

As previously stated, any suitable riddle or other separating device may be employed in connection with the apparatus,

the type disclosed in my copending application Serial No. 359,943.

Referring to Figure 8, the numeral 86 designates a supporting framework as a whole to the lower end of which the separating device per se indicated as a whole by the numeral 81 is attached. A gyratory motion is imparted to the frame 8%, and hence to the pan 8?, by a motor 88 driving a shaft 89 having an eccentric weight 90 at its lower end.

Referring to Figure 9 it will be noted that the separator 871 comprises generally a cylindrical pan at in the lower portion of which is secured a screening element d2 backed up by a relatively heavy screen 933. Oversize material retained on the screen $2 is discharged from the pan at through an opening 9% which communicates with and in Figures 8 and 9 of the drawings 1 have illustrated a riddle of one of the discharge spouts 8% previously described. It will be apparent that the separator V as a whole has been indicated diagrammatically by the numeral 63 in Figure l of the drawings. Accordingly it will be obvious that material passing through the screen 92 of each separating device falls downwardly to the associated pan it, H or 56 and that oversize material will be discharged from the spouts of the separating devices into either the trough 30 or duct 53. Material is fed into the pan of each separator through a flexible pipe 95 connected to an inlet spout 9t, and the incoming material is spread overthe screen 92 by a spreader 9h The operation of the apparatus is as follows:

The slurries or other materials to be treated are fed into the headbox 65 through the inlet pipe 68, this operation preferably taking place continuously. The material is permitted to accumulate in the headbox until it reaches the height of the upper edge of the wall 12, whereupon the valves associated with the piping connections are opened. It will be apparent that the maintenance of the height of the liquid a substantial distance above the discharge openings I3 insures a uniform supply of material to the pans i6 and I! through the piping connections referred to. In order to insure the maintenance of the height of material in the headbox 65, material is preferably fed thereinto at a rate exceeding the rate of discharge of material through the pipes W. The excess material overflows the wall 12 and is drained from the headbox through the pipe Wand returned to the source of material. In the event material is fed too rapidly into the headbox 65, or the pipe Hi becomes clogged, the take-01f pipe H comes into the excess material and from overflowing.

Material discharged from the headbox flows downwardly through pipes 18, valves 15, pipes 16, It and I8, and thence through the pipes 82 to slurries occurring" in the manufacture of paper pigments the fine material and arated from the grit and are -i'ed downwardly through the screens 92 or theseparating devices arranged over the pans l6 and I! and are discharged to these pans. The coarse material such solubles are sepas the grit, is retained on the screens 92 and is progressively discharged from the separating devices through the spouts '64, and this material is discharged into the trough 30. v

A washing liquid such as water is fed into the trough 30 through the pipe 36' and the liquid in the trough is maintained somewhat below the level of the upper end of the discharge spout 34,-

by virtue of the factthat the entrance to duct 52 is somewhat lower than the upper end of the discharge spout 34. a The water and material collected thereby flows-out of the trough 30 in a manner to be described, and since this flow takes place relatively' slowly,'the supply of water to a correspondingly slow rate.

The coarse material falling into the trough 30 is subjected to'a'. washing action by water therein', and accordingly-the fine material and solubles which adhere to the grit will be substantially completely removed therefrom. The plate 4| is provided to prevent thegrit falling into the trough adjacent the outlet end thereof from bethe trough through the pipe 36' takes place at ing removed from the trough before being completely washed. The'scrapers 39 ;of the upper runs of the chains act to carry the grit falling upon the plate 4| toward the lower end of the trough 30 to insure the complete subjection of such grit to the'washing action of the water.

The grit sinks down to the" bottom oi. the trough 30 beneath the lower end of the plate 41 and is picked up by'the scrapers 39 of the lower runs of thechains and moved upwardly toward the spout 34 to be discharged from the apparatus ina substantially clean condition.

The water enters at the discharge end of trough 30, passes downwardly between the bottom of the trough and plate I; thus acting in a counter current manner to wash the grit being conveyed up the inclined bottom by the scrapers 39 attached to lower runs-of the chains 30. The scrapers 39 attached to the upper runs of the chains serve to convy rit falling upon plate ll to they lower end ofplate 4|, where the grit falls through an ascending. stream of wash liquid.

\ The scrapers 39v attached to the portions of the upper runs oi-the chains 38 between thelower end ofplate ll and sprocket it serve as an effective means of agitating slowly the descend-- ing grit in the ascending washing liquid, and thus promote the eflective washing of the grit.

The flow of washingliquid into the apparatus is at a relatively slow rate, as it has been found that the apparatus functions eflfectively with relatively small quantities of washing liquid. Thus the flow of liquid into the duct 52 is sufficiently' slow so that substantially no grit is carried over with the fine material in the wash-' ing liquid;' Moreover the'amount of washing liquid, being small in volume, can be finally in- 'troduced into the tank containing the original the grit by the washing action flow from the duct 52 into the trough '53 and are discharged from the end thereof through the pipe 54.

The fine material and solubles separated from the grit by the devices 63 arranged over the pans l6 are deposited in these pans and flow into the pans lI through the transverse ducts 2|. This material accordingly is discharged fro the pans into the pans I I where it mingle with the fine materials and solubles separatedfrom the grit by the devices 63 arranged over the pans ll. The separated materials from each of the pans l1 flows therefromthrough the openings 26 and pipes 21 and 28 and are thus discharged into the separating devices 63 arranged over the pans 5.

The auxiliary separating apparatus comprising the devices 63 arranged over the pans 56 is provided as a safety measure to prevent the discharging of fine materials and solubles containing any coarse materialpr grit which might be mixed therewith due to the breaking oroverflowing of any of the screens of the devices 63 arranged over the pans l 6 and I1. The auxiliary separating de-' vices operate in the same manner as the separating devices of the main portion of the apparatus. The fine material and solubles will be deposited in the pans 55 and will flow therefrom through the outlet openings 58 into the pipes 60, from which the materials will be delivered to the take-oil pipe 62 to be collected therefrom. Any coarse material which may have been deposited upon the screens of the pans 56 will be discharged through the spouts 64 of the devices 63 of the pans 58 into the trough 53.

It-will be noted that for each two initial sepa- -rating devices, but .one auxiliary separating de- \vice is provided. The reason for this is that the capacity of the initial separating devices is limited owing to presence of grit in the slurry, but that the substantially grit-free slurry delivered from the initial separating devices passes much more rapidly through the auxiliary separating device, so that one auxiliary readily handles the efliuent irom two initial separating devices.

It will be apparent that under normal operating conditions substantially all of the material finding its way into the trough 53 will .be in the form of fine material and solubles and if there rated. The wash liquor coming from duct 52 is usually suflicient in quantity to carry along with it all grit dropping into trough 53. If it is not, an additional stream of liquid such as water may be applied for this purpose. The material drawn oil! through the pipe 62 will be in proper condition for use, having been subjected to the two separating actions taking place in the main and auxiliary separators.

the source of supply to-be rescreened and sepa- It has been found that the use of the headbox 65 with piping connections as described insures a uniform supply of material to the riddles or separators, and it also substantially prevents the settling of the slurry and the consequent clogging of the piping connections. The constant supply of material to the headbox through pipes 68 serves to maintain the material in the box in a state of constant agitation to prevent the settling action refered to.

From the foregoing it will be apparent that the present apparatus provides for both separation or classification of the material, and for the washing thereof to prevent the loss of any valuable material which may adhere to the grit after the latter has been subjected to the separating action. 'It also provides a method whereby the washing action is combined with a classification feature whereby fine solids may be separated from the grit at the same time as the grit'is freed of soluble material. The apparatus is continuous and efficient in operation, the efficiency of the system resulting from the combination of the washing and classifying action with the separating action.

From the foregoing it will be apparent that the present apparatus provides for the carrying out of the method involved wherein the material to be treated is first subjected to a separating action, and wherein the coarser material separated from the mass is subjected to a washing action to prevent the loss of material passing out of the apparatus with the grit.. The method further contemplates a two-stage separating action to insure a supply of fines and solubles without the presence of any coarse material therein, and any coarse material separated in the second separating stage is returned to the material washed from the grit to be reseparated.

It is to be understood that the form of appatus shown and described and the details of procedure of the method may be varied without departing from the spirit of the invention or the scope of the subjoined claims. I claim:'

1. Apparatus of the character described comprising a pair of separating devices each including a screen, means for supplying material to the screens of said separating devices, a pair of pans adapted to be arranged beneath the respective screens of the separating devices to receive material passing through the screens, a connection between said pans adapted for the flow of liquids, a washing through for receiving from said separating devices the material retained on the screens thereof, means for supplying a washing liquid to said trough, a duct for drawing off the washing liquid and material therein from said trough, a third separating device including a screen, a third pan adapted to be arranged beneath the screen of the third separating device,

means for delivering material received in said pair of pans to thescreen of the third separating device, and means for delivering material retained on the screen of the third separating device to said duct.

2. Apparatus of the character described comprising a separating device including a screen, means for supplying material to said screen, a pan arranged beneath said screen to receive material passing therethrough, a washing receptacle adapted to receive material retained on said screen, means for supplying a washing liquid to said receptacle, a duct for drawing off the washing liquid and material therein from said receptacle, a second separating device including a screen, means for conducting material from said pan to the screen of said second separating device, a second pan arranged beneath the screen of said second separating device, and means for delivering material retained on the screen of said second separating device to said duct.

3. Apparatus of the character described comprising a pair of separating devices each including a screen, a pair of receivers arranged beneath the screens of the respective separating devices to receive material'passing through said screens, the bottom of one of said receivers sloping downwardly toward the other receiver, a connection between said receivers, the bottom of said connection and the bottom of said other receiver being sloped and lying in the plane of the sloping bottom of said first named receiver, and single means for drawing off material from said other receiver adjacent the low'point in the bottom thereof.

HAROLD ROBERT RAFION. 

